In the printing field, there have been numerous ways and means for impressing a mark or indicia on record media, one common means being the use of a rubber or like porous stamp or pad which carries a limited supply of ink therein for making at least one and perhaps another impression. As improvements in porous material were made available, the ink pad was able to retain sufficient ink therein for repeated impressions without re-inking the pad. More recently, there have been provided devices associated with the stamp or pad which tend to supply the pad with the proper amount of ink or to maintain sufficient ink within the pad or stamp for such repeated impressions.
In modern business machines, the number of required impressions is, of course, greatly increased by the volume of documents or like record media which must be processed in day-to-day operations. In order to supply a quantity of ink to the impression stamp or pad and to control the flow of ink to the pad, it is a basic requirement that sufficient ink be permitted to flow to the pad so as to each time have a legible mark on the record media, and that precautions be taken to prevent an over supply of ink to flow to the pad which would result in smudging of the mark or indicia.
In regard to means for controlling the flow of ink to a printing member and/or to a printing surface, representative ways and means are disclosed in prior art relevant to the present invention. One example is British Patent No. 1,241,794, inventor H. F. Farrow, which shows printing apparatus having a piston, a cylinder carrying a hollow piston connected with the cylinder through one opening and connected with a chamber through other openings. The first-mentioned piston has a ball valve biased by a spring to a position in which it closes one passage to the chamber and also prevents passage of ink between the chamber and its outlet. Operation of the pistons causes closing of certain ports and opening of the outlet to allow ink to flow to the printing surface, and when sufficient ink has been supplied, the pressure in the chamber increases and the ball valve is lifted from its seat to allow excess ink to return to the supply through one passage to the chamber. As pressure is released, the hollow piston is moved so that the outlet is closed by the ball valve. Further reduction of pressure moves the first-mentioned piston to open the chamber inlet ports and ink flows from the supply to the chamber for the next operation.
U.S. Pat. No. 1,343,633, issued to S. G. McPheters, discloses an automatic marking or stamping device having a head, a wick-receiving chamber, and a wick communicating with a chamber connected with a fluid tank through a supply pipe. A valve cooperates with a valve seat in the pipe and has a stem connected with a bridge-piece adjacent the chamber, the valve being loaded on the seat by a spring. Pressure on the face of the head unseats the valve and allows fluid to flow from the pipe to the head and through the various apertures for making a mark.
U.S. Pat. No. 3,072,053, issued to G. Becker et al., shows an inking device for inking ribbons, felt rollers, and rubber coatings, and has an inking roller covered with felt or porous rubber material which becomes impregnated by ink entering through bores into several grooves. Another inking roller has a closure valve comprising a ball and a spring for convenient filling of the roller.
U.S. Pat. No. 3,376,812, issued to R. E. Sterling, discloses a reciprocal porous printing member with ink reservoir feed wherein a reservoir is connected with a solenoid to be moved thereby along with a porous printing member, while a U-shaped member is secured to a frame to remain fixed. The reciprocating motion of the reservoir between a non-printing and a printing position is used to transfer and to seal off the ink supply in the reservoir to the porous printing member. A portion of the reservoir has an area with spaced apertures for ink flow to the porous printing member. A second porous member attached to the U-shaped member covers the spaced apertures and, in the non-printing position, certain areas of the U-shapedmember press on the second porous member and block the flow of ink. When the solenoid is energized, the reservoir is pushed towards the paper on the platen and away from the U-shaped member, and the second porous member soaks up the ink in the areas adjacent the spaced apertures. A spring restores the solenoid and the reservoir towards the U-shaped member, and the second porous member contacts the areas to compress the porous member to seal off the flow of ink to the spaced apertures.
And, U.S. Pat. No. 3,536,007, issued to A. J. Harvey, discloses a self-inking laminated die plate having resilient mats separating an upper plate and a base, the plate having a supply line from a reservoir to an ink cavity, the supply line including a one-way check valve permitting ink flow to the cavity. A second one-way check valve is in a line from the cavity to a second reservoir to allow fluid flow to the cavity. A die plate is located adjacent the article to be printed and rests on an apertured platform whereby pressure exerted by the article on the plate causes the plate to yield and decreases the volume of ink in the cavity. The ink flows through the apertures in the platform and through the lines in the die plate. When the pressure is relieved, the volume of the cavity increases and ink flows through the lines to the cavity.